Inspection of the electric characteristics of electronic circuits such as an IC and an LSI formed on, for example, a semiconductor wafer is conducted by using a probe card fitted to a prober. A probe card generally has a circuit board and a contactor. A number of probes are supported on an undersurface of a contactor opposed to a wafer, and the probe is constructed by, for example, a contact to be brought into contact with the wafer, and a beam part which supports the contact at its tip end portion, is slim and long, and has flexibility and elasticity. Inspection of the electric characteristics of a wafer is conducted by bringing contacts of a plurality of probes into contact with each of electrodes of the electronic circuit.
In order to conduct inspection of the electric characteristics properly, it is necessary to bring each of the contacts of a plurality of probes into contact with a wafer at a constant pressure, and when differences exist in distance between the respective probes and the wafer, such differences have to be absorbed. Therefore, it is necessary to give sufficient flexibility to the beam part of each of the probes, and a space allowing the contacts to move has to be sufficiently secured for realizing sufficient mobility of the contacts in the direction of the wafer.
Conventionally, in order to attain such an object, a support post 201 having a certain height is formed at an electrode 200a on an undersurface of a contactor 200, and a beam portion 202a of a probe 202 is joined to the support post 201, as shown in, for example, FIG. 17. Thereby, a contact 202b can move to the contactor 200 side, and a space allowing the contact 202b to move is secured (see Patent Document 1). As another method, a recessed portion 203 in a concave shape is formed at an undersurface side of the contactor 200 as shown in, for example, FIG. 18, and a space allowing the contact 202b to move is secured (see Patent Document 2).
However, in the case of joining the probe to the support post of the contactor as in the former, a number of support posts having certain heights have to be formed corresponding to the number of probes in an extremely narrow and small area in the undersurface of the contactor, and therefore, it is technically very difficult to form the position and shape of each of the support posts with high accuracy. In the case of forming the recessed portion in the contactor as in the latter, wiring for passing electricity to the probe cannot be provided at that portion, and therefore, degree of freedom of design of wiring in the contactor is lost, thus limiting the installing positions and the number of probes.
Incidentally, in a probe card, a circuit board is overlapped on a contactor supporting probes. Inspection of the electric characteristics of a wafer is conducted by bringing a plurality of probes into contact with the electrodes of the electronic circuit of the wafer, and by applying an electric signal for inspection to each of the electrodes of the electronic circuit from each of the probes through the circuit board and the contactor.
Since inspection of the electric characteristics is conducted in a wide range of temperature region of, for example, minus 20° C. to 150° C., it sometimes happens that a circuit board expands and contracts due to, for example, thermal influence at the time of inspection, and flatness and horizontality of the circuit board are sometimes reduced. Therefore, electrical contact of the circuit board and the contactor becomes unstable in the circuit board or the contactor surface, and inspection is not sometimes conducted properly. In order to solve such a problem, it is proposed at present to dispose an interposer constituted of a board with interconnection elements in spring form mounted on a top and a bottom surfaces between a contactor and a circuit board, for example (see Patent Document 3).
However, when the interposer constituted of a plurality of members as described above is mounted between the circuit board and the contactor, the structure of the entire probe card is complicated. Since the above described interposer takes a width in the vertical direction, for example, the contactor and the circuit board separate from each other, and the entire probe card becomes large in size. Further, it is necessary to form a spring in a specific shape, mount the spring on the top and the bottom surfaces of the base board, and mount the base board to a specific position between the circuit board and the contactor precisely, and therefore, manufacture of the probe card becomes difficult.
[Patent Document 1] Japanese Patent Application Laid-open No. 2003-215161
[Patent Document 2] Japanese Patent Application Laid-open No. 2000-346878
[Patent Document 3] Translated National Publication of Patent Application No. Hei 10-506197 (FIG. 5)